1. Field of the Invention
The present invention relates generally to a heat dissipation device, and particularly to a heat dissipation device for a heat generating electronic device.
2. Description of Related Art
With the continuing development of the electronic technology, electronic packages such as CPUs (central processing units) are generating more and more heat that requires immediate dissipation. Cooling fans are commonly used in combination with heat sinks for cooling CPUs.
Oftentimes, the heat sink includes a plurality of fins stacked together. Each fin is planar and parallel to each other. A flow channel is formed between two adjacent fins. The cooling fan is arranged at a side of the heat sink, facing the flow channels thereof. During operation, the heat sink absorbs the heat generated by the CPU. The airflow generated by the cooling fan flows through the flow channels to exchange heat with the fins. Then the heat is dissipated to surrounding environment by the airflow. Thus, heat dissipation of the heat generating device is accomplished.
For the planar shape of the fins, each of the flow channels has a constant size along the flowing direction of the airflow. Due to viscosity, a laminar air envelope may be formed at a surface of each of the fins of the heat sink when the airflow flows through the heat sink. The flowing speed of the airflow in this laminar air envelope is nearly zero, whereby the degree of heat exchange between the airflow and the heat sink is greatly reduced. Therefore, the airflow flowing through the heat sink cannot sufficiently assist the heat dissipation from the fins to the surrounding environment, wherein the fins absorb the heat from the heat-generating electronic package. Accordingly, heat dissipation effectiveness of the conventional heat sink is limited.
For the foregoing reasons, therefore, there is a need in the art for a heat dissipation device which overcomes the above-mentioned problems.